===============================================================================
Security Advisory                                                       CERT-NL
===============================================================================
Author/Source : CERT-NL                                     Index  :    S-92-12
Distribution  : SURFnet Constituency                        Page   :          1
Classification: External                                    Version:      final
Subject       : SunOS /usr/etc/rpc.mountd Vulnerability	    Date   :  28-may-92
===============================================================================

CERT-NL (SURFnet Computer Emergency Response Team) has received
information concerning a security problem in SunOS /usr/etc/rpc.mountd.

CERT-NL wishes to thank CERT/CC for bringing this to our attention.

===========================================================================
CA-92:12                      CERT Advisory
                              May 28, 1992
         Revised Patch for SunOS /usr/etc/rpc.mountd Vulnerability

---------------------------------------------------------------------------

                   *** THIS IS A REVISED CERT ADVISORY ***
          *** IT CONTAINS NEW VULNERABILITY AND PATCH INFORMATION ***
                  *** SUPERSEDES CERT ADVISORY CA-91:09 ***

The Computer Emergency Response Team/Coordination Center (CERT/CC) has
received information concerning the availability of a revised security
patch for /usr/etc/rpc.mountd in Sun Microsystems Computer Corporation
operating systems.  This patch fixes an additional vulnerability that
was not addressed in CERT advisory CA-91:09.SunOS.rpc.mountd.vulnerability.

Sun has provided patches for SunOS 4.1, SunOS 4.1_PSR_A, SunOS 4.1.1,
and SunOS 4.1.2.  These patches are available through your local Sun
Answer Center as well as through anonymous ftp from ftp.uu.net (137.39.1.9)
in the /systems/sun/sun-dist directory.

Patch ID and file information are as follows:

Fix                     Patch ID       Filename            Checksum
/usr/etc/rpc.mountd     100296-02      100296-02.tar.Z     30606    23

Please note that Sun Microsystems sometimes updates patch files.  If you
find that the checksum is different, please contact Sun Microsystems or
the CERT/CC for verification.

---------------------------------------------------------------------------
I.   Description

     Under certain conditions an exported NFS filesystem can be
     mounted by any system on the Internet even though it may appear
     that access to the filesystem is restricted to specific hosts.

II.  Impact

     Unauthorized remote hosts will be able to mount the exported filesystem.

III. Solution

     As root:

     1.  Move the existing rpc.mountd aside and change the permissions.

         # mv /usr/etc/rpc.mountd /usr/etc/rpc.mountd.OLD
         # chmod 400 /usr/etc/rpc.mountd.OLD

     2.  Install the new version

         # cp `arch`/rpc.mountd /usr/etc
         # chown root.staff /usr/etc/rpc.mountd
         # chmod 755 /usr/etc/rpc.mountd

     3.  Kill the currently running rpc.mountd and restart it, or
         reboot the system.  In either case, systems with filesystems
         mounted from this host will have interruptions in service.

---------------------------------------------------------------------------

==============================================================================
CERT-NL is the Computer Emergency Response Team, located in The
Netherlands. CERT-NL is a Full Member of the Forum of Incident Response
and Security Teams (FIRST). The constituency of CERT-NL are the SURFnet
connected institutions.

Past CERT-NL Security Bulletins and other CERT-NL related material can
be found on the anonymous FTP server of SURFnet bv:
"ftp.nic.surfnet.nl" [192.87.46.3], in the directory "netman/cert-nl".
This information is also available using email. Send an email saying
"help" to "mailserv@nic.surfnet.nl".

In case of computer or network security problems please contact CERT-NL
or the CERT of your own constituency. Please be aware of the fact that
we are are one hour ahead of Universal Time Coordinated (i.e. UTC+0100).
Email:     cert-nl@surfnet.nl
Phone:     +31 30 310290
Fax:       +31 30 340903
Snailmail: SURFnet bv
           Attn. CERT-NL
           P.O. Box 19035
           NL - 3501 DA  UTRECHT
           The Netherlands
A 7*24h phonenumber is available to SURFnet SSC's and FIRST members on request
==============================================================================